<style>

.outer {
    border: 4px solid black;
    width: 100px;
    height: 100px;
    border-radius: 40px;
    background-color: lightblue;
    overflow: hidden;
    margin: 10px;
}

.inner {
    width: 80px;
    height: 80px;
    background-color: green;
    padding: .5em;
    will-change: transform;
}

.dashed {
    border-style: dashed;
}

.transparent {
    border-color: rgba(255,0,0,0.5);
}

</style>

<div class = "outer">
    <div class = "inner"></div>
</div>

<div class = "outer dashed">
    <div class = "inner"></div>
</div>

<div class = "outer transparent">
    <div class = "inner"></div>
</div>
